항공기날개형상설계를 위한 distributed design의 적용

김태희,최성임 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

항공기는 연관된 매우 많은 하위 시스템들로 이루어져 있기 때문에 이에 대한 설계는 매우 어려운 일이다. 그러므로 항공기 설계에 있어 각 분야들을 따로 생각하는 것은 의미가 없으며 이들에 대한 연관성을 고려하여 통합적인 해석이 매우 중요하다. 다분야 최적설계는 이러한 문제들을 해결하는 방법론으로서 최근 많은 연구가 진행되고 있다. 본 연구의 목적은 다분야 최적설계 방법론을 항공기 날개 설계에 적용해 보는 것이다. Distributed design은 다분야 최적설계의 한 방법으로서 전체 문제를 상위수준과 하위수준으로 나누어 각 분야에 독립적인 역할을 부여하는 방법이다. Collaborative Optimization(CO)와 Concurrent Sub-Space Optimization(CSSO)는 distributed design의 일종으로 서로 다른 형태와 특성을 가지고 있다. 본 연구에서는 간단한 예제를 통해 CO와 CSSO의 장단점을 알아보고 이를 항공기 날개 형상 설계에 적용해보기로 한다. Aircraft design needs considerable effect because aircraft is composed of many subsystem which are highly coupled. Therefore, decoupled analysis of an aircraft design is meaningless and it is important to perform an integrated analysis. A multidisciplinary Design Optimization(MDO) is methodology that tries to solve those issues and many researches are performed recently. The purpose of this study is application of MDO to aircraft wing design. A distributed design which is one of MDO divides the aircraft system into system and subspace levels and distributes independent role to each discipline. Collaborative Optimization(CO) and Concurrent Sub-Space Optimization(CSSO) are kinds of distributed design which have different formulations and characteristics. In current study, we compare CO and CSSO about their advantages and weakness through analytic function and they are applied to aircraft wing shape design.

Multidisciplinary wing design optimization considering global sensitivity and uncertainty of approximation models

박형욱,정준,Kamran Behdinan,이재우 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6

In recent years, high-fidelity analysis tools, such as computational fluid dynamics and finite element method, have been widely used inmultidisciplinary design optimization (MDO) to enhance the accuracy of design results. However, complex MDO problems have manydesign variables and require long computation times. Global sensitivity analysis (GSA) is proposed to assuage the complexity of designproblems by reducing dimensionality where variables that have low impact on the objective function are neglected. This avoids wastingcomputational effort and time on low-priority variables. Additionally, uncertainty introduced by the fidelity of the analysis tools is consideredin design optimization to increase the reliability of design results. Reliability-based design optimization (RBDO) and possibilitybaseddesign optimization (PBDO) methods are proposed to handle uncertainty in design optimization. In this paper, the extended Fourieramplitude sensitivity test was used for GSA, whereas a collaborative optimization-based framework with RBDO and PBDO wasused to consider uncertainty introduced by approximation models. The proposed method was applied to an aero-structural design optimizationof an aircraft wing to demonstrate the feasibility and efficiency of the developed method. The objective function was to maximizethe lift-to-drag ratio. The proposed process reduced calculation efforts by reducing the number of design variables and achieved the targetprobability of failure when it considered uncertainty. Moreover, this work evaluated previous research in RBDO with MDO for the wingdesign by comparing it with the PBDO result.

PIDO 기술을 이용한 전륜 현가계의 다분야 통합 최적설계

최병렬(Byung-Lyun Choi),이갑성(Gab-Seong Lee),최동훈(Dong-Hoon Choi),남찬혁(Chan-Hyuk Nam),김기훈(Gi-Hoon Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

In this research, a multidisciplinary design optimization of suspension system is executed using the process integration and design optimization technique. To obtain design requirements from multi-disciplines, such as weight, durability, crash, NVH, and K&C analysis, the shapes and thicknesses of front sub-frame are optimized. To define the shape design variables, a morphing technique is utilized. For maximizing the efficiency of multidisciplinary design optimization, we apply an approximate optimization technique and enhance the accuracy of approximate models with augment latin hypercube design sampling, which is one of practical additional design of experiments. We can understand the main effect of each performance using design sensitivity matrix after execution of design of experiments. The response surface method and kriging method are adaptively used. The thickness design variables are dealt as discrete variables so that we adopt an evolutionary algorithm as a discrete optimizer. We successfully obtain alternative designs using various design formulations changing the priorities of weight and fatigue life cycles.

Uncertainty-based MDO for aircraft conceptual design

Park, Hyeong-Uk,Lee, Jae-Woo,Chung, Joon,Behdinan, Kamran Emerald Group Publishing Limited 2015 Aircraft engineering and aerospace technology Vol.87 No.4

<P><B>Purpose</B></P> <P> – The purpose of this paper is to study the consideration of uncertainty from analysis modules for aircraft conceptual design by implementing uncertainty-based design optimization methods. Reliability-Based Design Optimization (RBDO), Possibility-Based Design Optimization (PBDO) and Robust Design Optimization (RDO) methods were developed to handle uncertainties of design optimization. The RBDO method is found suitable for uncertain parameters when sufficient information is available. On the other hand, the PBDO method is proposed when uncertain parameters have insufficient information. The RDO method can apply to both cases. The RBDO, PBDO and RDO methods were considered with the Multidisciplinary Design Optimization (MDO) method to generate conservative design results when low fidelity analysis tools are used. </P> <P><B>Design/methodology/approach</B></P> <P> – Methods combining MDO with RBDO, PBDO and RDO were developed and have been applied to a numerical analysis and an aircraft conceptual design. This research evaluates and compares the characteristics of each method in both cases. </P> <P><B>Findings</B></P> <P> – The RBDO result can be improved when the amount of data concerning uncertain parameters is increased. Conversely, increasing information regarding uncertain parameters does not improve the PBDO result. The PBDO provides a conservative result when less information about uncertain parameters is available. </P> <P><B>Research limitations/implications</B></P> <P> – The formulation of RDO is more complex than other methods. If the uncertainty information is increased in aircraft conceptual design case, the accuracy of RBDO will be enhanced. </P> <P><B>Practical implications</B></P> <P> – This research increases the probability of a feasible design when it considers the uncertainty. This result gives more practical optimization results on a conceptual design level for fabrication. </P> <P><B>Originality/value</B></P> <P> – It is RBDO, PBDO and RDO methods combined with MDO that satisfy the target probability when the uncertainties of low fidelity analysis models are considered.</P>

Collaborative Optimization을 이용한 지구관측위성의 다분야 통합 최적 개념설계

김홍래(Hongrae Kim),장영근(Young-Keun Chang) 한국항공우주학회 2015 韓國航空宇宙學會誌 Vol.43 No.6

본 논문에서는 다분야 통합 설계최적화(MDO : Multidisciplinary Design Optimization)를 적용한 지구관측위성의 개념설계 과정 및 결과를 기술하였다. 현재까지 구축된 지구관측위성의 데이터베이스를 기반으로 주요 파라미터에 대한 개념설계식을 정립하였으며, 다분야 통합 최적설계 아키텍처 중 CO(Collaborative Optimization) 기반을 이용하여 지구관측위성 시스템의 최적 개념설계를 수행할 수 있는 설계 도구를 개발하였다. 주어진 제약조건을 만족시키면서 위성의 총 질량을 최소화하는 것을 설계 목표로 설정하였으며, 최적화 알고리즘으로는 SQP(Sequential Quadratic Programming)를 이용하였다. 다분야 통합 최적 설계를 적용한 개념설계 결과와 ASNARO-1 및 IKONOS-2 위성 규격의 비교를 통해 해당 설계도구의 유용성을 검증하였다. In this paper, the conceptual design procedure and results of Earth observation satellite through Multidisciplinary Design Optimization (MDO) are described. The conceptual design equations for major parameters are developed based on the established database of Earth observation satellite so far. The MDO conceptual design tool for Earth observation satellite was developed by applying the Collaborative Optimization (CO) architecture amongst several MDO architecture techniques available today. The objective for this research was set to minimize the total mass of satellite as well as satisfy all design constraints by utilizing the Sequential Quadratic Programming (SQP) algorithm. Eventually the effectiveness of MDO conceptual design tool was verified through proposing a comparison between the conceptual design results with MDO applied and the design specification of ASNARO-1 & IKONOS-2 Earth observation satellite.

Development of an improved framework for the conceptual design of a rotorcraft

Lim, JaeHoon,Shin, SangJoon,Laxman, Vaitla,Kim, Junemo,Jang, JinSeok Emerald Group Publishing Limited 2014 Aircraft engineering and aerospace technology Vol.86 No.5

<P><B>Purpose</B></P> <P> – The purpose of the present paper is to obtain the capability of designing modern rotorcrafts with enhanced accuracy and reliability. </P> <P><B>Design/methodology/approach</B></P> <P> – Among the existing rotorcraft design programs, an appropriate program was selected as a baseline for improvement. It was based on a database comprising conventional fleets of rotorcrafts. The baseline program was not robust because it contained a simple iteration loop, which only monitored the gross weight of the aircraft. Therefore, it is not accurate enough to fulfill the quality and sophistication of a conceptual design framework useful for present and future generations of rotorcrafts. In this paper, the estimation formulas for the sizing and weight of the rotorcraft subsystem were updated by referring to modern aircraft data. In addition, trend curves for various turboshaft engines available these days were established. Instead of using the power estimation algorithm based on the momentum theory with empirical corrections, blade element rotor aerodynamics and trim analysis were developed and incorporated into the present framework. Moreover, the simple iteration loop for the aircraft gross weight was reinforced by adding a mathematical optimization algorithm, such as a genetic algorithm. </P> <P><B>Findings</B></P> <P> – The improved optimization framework for rotorcraft conceptual design which has the capability of designing modern rotorcrafts with enhanced accuracy and reliability was constructed by using MATLAB optimization toolbox. </P> <P><B>Practical implications</B></P> <P> – The optimization framework can be used by the rotorcraft industries at an early stage of the rotorcraft design. </P> <P><B>Originality/value</B></P> <P> – It was verified that the improved optimization framework for the rotorcraft conceptual design has the capability of designing modern rotorcrafts with enhanced accuracy and reliability.</P>

항공기 날개 형상 최적화를 위한 distributed design의 적용

김태희(TaeHee Kim),최성임(Seongim Choi) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5

Aircraft design is very difficult because aircraft is composed of many subsystems which are highly coupled. Therefore, aircraft design with decoupled analysis at subsystems is meaningless and it is important to perform an integrated analysis. Designers revise existing design methods or find a new design method for satisfying the complex design requirement, one of them is a Multidisciplinary Design Optimization(MDO) which is methodology that tries to slove those issues and many study is performed recently. A distributed design divides the aircraft system into system and subspace levels and distributes independent role to each discipline. Collaborative Optimization(CO) and Concurrent Sub-Space Optimization(CSSO) are kinds of distributed design which have different formulations and different characteristics. CSSO carries out system analysis and solves a series of sensitivity equations. Also CSSO contains concept of responsible coefficient and trade-off coefficient. In contrast, CO doesn’t has system analysis and sensitivity equation and uses concept of auxiliary variables and compatibility condition. In current study, we compare Collaborative Optimization(CO) and Concurrent Sub-Space Optimization(CSSO) methods about their advantages and weaknesses through their application to aircraft wing shape design problem.

Service ORiented Computing EnviRonment (SORCER) for deterministic global and stochastic aircraft design optimization: part 1

Raghunath, Chaitra,Watson, Layne T.,Jrad, Mohamed,Kapania, Rakesh K.,Kolonay, Raymond M. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.3

With rapid growth in the complexity of large scale engineering systems, the application of multidisciplinary analysis and design optimization (MDO) in the engineering design process has garnered much attention. MDO addresses the challenge of integrating several different disciplines into the design process. Primary challenges of MDO include computational expense and poor scalability. The introduction of a distributed, collaborative computational environment results in better utilization of available computational resources, reducing the time to solution, and enhancing scalability. SORCER, a Java-based network-centric computing platform, enables analyses and design studies in a distributed collaborative computing environment. Two different optimization algorithms widely used in multidisciplinary engineering design-VTDIRECT95 and QNSTOP-are implemented on a SORCER grid. VTDIRECT95, a Fortran 95 implementation of D. R. Jones' algorithm DIRECT, is a highly parallelizable derivative-free deterministic global optimization algorithm. QNSTOP is a parallel quasi-Newton algorithm for stochastic optimization problems. The purpose of integrating VTDIRECT95 and QNSTOP into the SORCER framework is to provide load balancing among computational resources, resulting in a dynamically scalable process. Further, the federated computing paradigm implemented by SORCER manages distributed services in real time, thereby significantly speeding up the design process. Part 1 covers SORCER and the algorithms, Part 2 presents results for aircraft panel design with curvilinear stiffeners.

날개끝 스토어 형상 항공기 복합재 날개 구조의 MDO 연구

전승문(Seung-Moon Jun),이명건(Myoung-Keon Lee),이재화(Jae-Hwa Lee) 한국항공우주학회 2004 韓國航空宇宙學會誌 Vol.32 No.2

본 논문에서는 날개끝 스토어가 장착된 항공기 복합재 날개구조에 대한 다분야 통합 최적화 설계를 수행하였다. 스토어 위치, 중량 및 공력효과 등을 고려하여 복합재 날개구조 설계 과정에서 중요한 고려인자가 무엇인지 파악하고자 하였다. 정적강도, 제작한계 및 플러터 속도를 구속조건으로 하여 ICW 날개 모델을 최적화 하였다. 각 요소의 두께와 단면적을 설계 변수로 사용하였다. 최적화 설계 도구로서 MSC/NASTRAN을 사용하였다. 실용적인 설계 관점에서 복합재 적층 파손식 적용을 검토 하였다. 날개끝 스토어의 공기력 효과가 ICW 날개 모델의 공탄성 불안정 특성에 큰 영향을 주었다. 최적화된 구조의 공탄성 불안정성이 날개끝 스토어가 날개 시위방향으로 움직임에 따라 아주 민감하게 변화하였다. 이러한 결과로 볼 때 날개끝 스토어 모델의 정밀도가 설계 과정에서 아주 중요한 인자임을 알 수 있었다. This paper presents MDO(Multidisciplinary Design Optimization) study results for aircraft composite wing structure with tip store. The objective is to identify key design parameters in the composite wing structure design process. The store location and the effect of the store aerodynamics and mass are the variables included. The ICW(Intermediate Complexity Wing) wing box model is optimized with constraints on the static strength, manufacturing limit and flutter speed. The thicknesses and the cross-sectional areas of the structural elements are the design variables in the optimization. The MSC/NASTRAN is the primary tool used in this study. Failure criteria of composite laminate are examined regarding the practical design. The aerodynamics of the tip store significantly affects the aeroelastic instability of ICW model. The aeroelastic instability of the optimized structure is very sensitive to the tip store movement along the tip chord. The present results indicate that the selection of tip store model fidelity is very important during the design process.

고효율 EAV 프로펠러의 다분야 최적설계

이슬기,권형일,최성임,박부민,강영석 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.4

전기추진 비행체용 프로펠러의 고효율화를 위해 다분야 최적 설계를 수행하였다. 특히 주어진 RPM에 따른 추력은 일정하게 유지하되 토크를 감소시켜 공기역학적 효율 향상을 도모하였으며, 동시에 고속 회전으로 인한 구조적 안정성을 보장하기 위해 구조해석을 수행하여 구조적 안정성을 검증하였다. 설계와 해석의 정확도를 높이기 위하여 비압축성 Euler 해석 기법의 CFD 알고리즘과 유한요소기법에 바탕을 둔 CSD (Computational Structural Dynamics)기법을 적용시켰다. 공력 및 구조 해석 기법의 정확도를 검증하기 위하여 EAV 의 운용조건에서 실험 블레이드의 풍동실험치와 비교되었다. 검증된 정확도를 바탕으로 토크감소를 위한 새 블레이드 형상 최적화가 수행되었다. 실험계획법, 크리깅 근사모델기법, 그리고 derivative-free 기법의 multi-objective genetic algorithm(MOGA)이 사용되었다. 설계 변수로는 프로펠러 블레이드 반경방향으로 8 개의 설계단면을 선정, 각 설계단면에서 비틀림 각과 끝 단 근처 3 개 단면에서의 코드길이, 앞 전 위치를 설계 변수로 선정하였다. 최적화된 형상에 대한 공력 해석과 구조해석을 수행한 결과, 토크가 약 5% 감소하였으며 구조적 안정성은 잘 보장되었다. A multidisciplinary design optimization of EAV (Electric Aerial Vehicle) propeller is carried out to maximize the efficiency of propeller performance. An objective is to minimize torque/power while maintaining a thrust level of baseline configuration at a given RPM and thus to improve propeller efficiency. Structural safety is also calculated during the design process and is ensured to satisfy a safety margin. A high-fidelity CFD and FEM-based structures computation is employed for a design. To test the accuracy of the analysis tools, a wind-tunnel test is conducted for the baseline propeller blade at operating RPM and numerical prediction is validated against experiment data. A derivative-free multidisciplinary design methodology based on the Kriging approximation model is used to achieve the design goal of minimization of torque. Design variables are mostly related to the shape of the blade and include twist distribution at eight cross sections along the blade span as well as the planform shape of the blade around tip area. Design results demonstrate a reduction of torque by almost 5 % at constant thrust. Safety margin is well satisfied for a new blade.